Laboratory diagnosis of Cyclospora infections.

The laboratory diagnosis of newly recognized infectious agents, such as Cyclospora cayetanensis, is frequently problematic because appropriate diagnostic techniques and algorithms are not available. The methods currently available for diagnosis of Cyclospora are described and compared, including concentration procedures, examination of wet preparations, various staining techniques, and the use of molecular-based assays. Because of the autofluorescent properties of the oocysts, particular attention is drawn to the role of fluorescent microscopy in providing a rapid, inexpensive, and sensitive technique for diagnosis of Cyclospora infections in stool samples. In addition to text descriptions, photomicrographs are provided to illustrate Cyclospora oocysts in wet and stained preparations and compare them with Cryptosporidium and Isospora oocysts, the other two most common coccidian infections in man.